In a conventional network system, a base station node and plural branch station nodes perform multi-hop wireless communication (see, e.g. PTL 1).
In this network system, the branch station nodes are connected to respective measurement devices. In the case that the base station node requests data to a branch station node connected to a measurement device while a communication path to this node has not been established, the base station node sends a request packet requesting the data in broadcast without specifying a destination branch station node.
When a branch station node receiving the request packet from the base station node finds that a destination address of this packet does not agree with a device ID of the branch station node, the branch station node functions as a relay node, and sends the request packet to other branch station nodes in broadcast. Thus, branch station nodes receive and transfer the request packet in broadcast one after another, thereby allowing the request packet to be finally received by a destination branch station node connected to the measurement device. This destination branch station node generates an acknowledge packet in reply to the request packet from the base station node and sends this acknowledge packet in unicast to a specific node. A header of the acknowledge packet contains a device ID of the branch station node that generates the acknowledge packet and information about a communication path to the base station node. Thus, the branch station nodes receive and transfer the acknowledge packet in unicast one after another, thereby the acknowledge packet to be finally received by the base station node.
In this network system, however, it may take long time to establish the communication path.
Moreover, in a wireless communication system, data collision between nodes may degrade communication quality and increases data retransmission to increase power consumption.